1. Field of the Invention
This invention relates generally to downhole cutting tools and clean-out methods and more particularly, but not by way of limitation, it relates to tubular goods clean-out tools of a type having upwards or downwards traversing capability with an expandable cutting tool that removes debris or other downhole material that was heretofore difficult to work.
2. Description of the Prior Art
The prior art has seen a number of different downhole tools for use in such as cutting casing, underreaming, notching along a formation, enlarging the borehole and various other operations as performed by larger diameter tools. However, the present invention is concerned with cleaning and cutting tools of smaller diameter. Casing fixed downhole in a wellbore sometimes needs to be cleaned of cement, sand, shale, mud and other types of deposits as it is encountered in the oil and gas industry. This requires a type of tool that can be lowered through a relatively narrow diameter tubing string to clean first the tubing string and subsequently the area immediately below or around the tubing string, i.e., the relatively wider diameter casing. "Thru tubing" clean-out tools as used for clean-out, cable cutting, tubing cutting and the like, have been developed and sold by Kat Tool, Inc. of New Iberia, La. This clean-out tool functions to remove scale and earth fill from the well bore below a packer without the necessity for drilling out the packer. Such clean-out tools may be run on small tubular goods as pump pressure is utilized to extend expansible knife blades as rotation and pumping will circulate out any debris.
U.S. Pat. No. 2,822,150 discloses a borehole enlargement tool, a rotary expandable drill bit, which extends blades laterally to function as rotary cutters. Outward extension of the cutter bars is accomplished by longitudinal movement of a plunger that is engaged to turn cutter blades about a rotary axis.
U.S. Pat. No. 2,284,170 provides a teaching where lateral cutters are actuated to an outward operating position in response to fluid pressure present internally in the drill string. A cutter actuating plunger is moved downward under fluid pump pressure thereby to actuate the cutter blades outboard from the longitudinal axis of the tool. Actually, the tool is intended for scraping of the borehole wall.
U.S. Pat. No. 3,050,122 discloses a formation notching apparatus having expansible cutter blades that are actuated to the outboard of a rotating cutting tool thereby to notch the borehole wall. Such notching is utilized for formation indication. This particular tool includes a casing cutting capability as well as the notching apparatus and each is operated in similar manner in response to downhole fluid pressure.
More to the point is the present inventor's prior U.S. Pat. No. 4,809,793 which expressly teaches a tubing tool for utilization in cleaning out deposits immediately below the tubing string and next to the well casing. This device uses an over and under alignment of expansible stabilizer blades over expansible cutter blades that are actuated by the drilling fluid pressure to spread their respective blades outward within the confines of the tubing and/or casing. This patent utilizes pressure driven pistons located above the respective stabilizer and cutter blades, and effective under pressure to move downward and force rotation of the blades outboard to their expanded position.